def get_multievent(cum_trace, tmin, tmax,
threshold_inside_tmin_tmax_percent,
threshold_inside_tmin_tmax_sec, threshold_after_tmax_percent):
"""
Returns the tuple (or a list of tuples, if the first argument is a stream) of the
values (score, UTCDateTime of arrival)
where scores is: 0: no double event, 1: double event inside tmin_tmax,
2: double event after tmax, 3: both double event previously defined are detected
If score is 2 or 3, the second argument is the UTCDateTime denoting the occurrence of the
first sample triggering the double event after tmax
:param trace: the input obspy.core.Trace
"""
tmin = utcdatetime(tmin)
tmax = utcdatetime(tmax)
double_event_after_tmax_time = None
d_order = 2
# split traces between tmin and tmax and after tmax
traces = [cum_trace.slice(tmin, tmax), cum_trace.slice(tmax, None)]
# calculate second derivative and normalize:
derivs = []
max_ = None
for ttt in traces:
sec_der = np.diff(ttt.data, n=d_order)
_, mmm = _maxabs(sec_der)
max_ = np.nanmax([max_, mmm]) # get max (global) for normalization (see below):
derivs.append(sec_der)
# normalize second derivatives:
for der in derivs:
der /= max_
result = 0
# case A: see if after tmax we exceed a threshold
indices = np.where(derivs[1] >= threshold_after_tmax_percent)[0]
if len(indices):
result = 2
double_event_after_tmax_time = timeof(traces[1], indices[0])
# case B: see if inside tmin tmax we exceed a threshold, and in case check the duration
indices = np.where(derivs[0] >= threshold_inside_tmin_tmax_percent)[0]
if len(indices) >= 2:
idx0 = indices[0]
idx1 = indices[-1]
deltatime = (idx1 - idx0) * cum_trace.stats.delta
if deltatime >= threshold_inside_tmin_tmax_sec:
result += 1
return (result, double_event_after_tmax_time)
def maxabs(trace, starttime=None, endtime=None):
"""
Returns the maxima of the absolute values of the trace or stream object passed as first
argument. The returned value is the tuple:
(time, val)
if trace is an obspy.Trace, or the lost:
[(time1, va1), ... (timeN, valN)]
if trace is an obspy.Stream
All times are UTCDateTime objects
:param trace: the input obspy.core.Trace
:param starttime: an obspy UTCDateTime object (or integer, denoting a timestamp) denoting
the start time of the trace, or None to default to the trace start
:param endtime: an obspy UTCDateTime object (or integer, denoting a timestamp) denoting
the start time of the trace, or None to default to the trace end
"""
tra = trace.slice(starttime, endtime)
idx, val = _maxabs(tra.data)
time = timeof(tra, idx)
return (time, val)
